Filter heater



W. S. CRAKE FILTERHEATER July 27, 1948.

3 Sheets-Sheet 1 Filed Oct. 1, 1946 FIG. l

wnfd sl Cmke. V

By His AH'orney Inven'for 2 July 27, 194s.

Filed Oct. 1, 1946 w. cRAKE 2,446,126

Fwmmnm'rsn 3 Sheets-Sheet 2 J zo FIG. 2

lnveror- Wilfred S. Crakc By His AHorreyi, l

July 27, 1948. w. s. cRAKE 2,446,126

I FILTER-HEATER Filed oct. 1, 1946 y 3 sheets4sheet`3 FIG.4

By His AHorney:

Patented July 2.7,' 1948 FILTER HEATER Wilfred S. Crake, Houston, Tex.,assigner to Shell Development Company, San Francisco, Calif., a

corporation of Delaware Application october i, 194s, serial No. 700,430

4 Claims. 1

The present invention relates to fluid filters. and is particularlydirected to a filter having filtering surfaces capable of beingmaintained at a desired temperature, whereby the accumulation of certainclogging materials on said filtering surfaces may be prevented, and/orsaid materials may be removed from the filter by the application ofheat.

When filtering a fluid such, for example, as mineral oil, the parafiinor asphalt in the oil tends to clog the filter to a 4considerableextent. According to the present invention, a wire or screen filter formineral oil or other liquids. has been found rto be practical when meansare provided to heat the screen in order to preven't it from beingclogged bythe paraffin or other deposits from the liquid being filtered.

While lfiltering materials having relatively high melting points, it ishighly essential to maintain the temperature of said materials above acertain level to keep them in a fluid condition. At the same time, it isnecessary to keep the filtering surface at or above vthe sametemperature to prevent it from clogging or freezing when fiow of fiuidis interrupted, as in the manufacture of 'commercial grades oftrinitrotoluene. Since this material freezes at about 80 C., it isnecessary to heat the process equipment including valves, pipe lines,filters and vessels which handle said material in a molten condition.clogging of the filters in such a case is a serious thing as it shutsdown an entire production line.

It is therefore an object of this invention to provide a filteringIapparatus wherein the filtering element may be heated.

It is a further object to ,provide a filter of simple and compact designhaving a structure that is economical in material and fabrication.

A still further object of this invention is to provide ya filteringapparatus capable of selfcleaning action of the filtering surf-acethrough the application of heat to said surface.

Another object of this device is to provide a filtering apparatus havingmeans for the accumulation and easy removal of materials removed fromfiltered fiuid or from the filtering surface.

In accomplishing these and other objects of the invention, an improvedstructure has been provided, the preferred forms of which areillustrated inthe accompanying drawings, wherein:

Fig. 1 is a diagrammatic view in longitudinal section of ya particularembodiment of a combinainvention.

Fig. 2 is a cross-sectional view taken along the line 2 2 in Flgrl.

Fig. 3 is a `cross-sectional view taken along the line 3-3 in Fig. 1.

Figs. 4, 5, 6 and 7 are diagrammatic views in vcross-section showingslightly modified embodimen-ts oi the present invention.

Briefly, the filter-heater comprises a central tubular mandrel,longitudinal ribs mounted radially to the long axis of the mandrel andformed or fabricated integrally with the mandrel, wrappings of wiresupported on said ribs, said ribs being sufficiently high 'to permitfree passage of liquid under the wires, an outer casing surrounding thewire wrapped mandrel, inlet and outlet liquid ports and a residue drainport in said casing. baffle elements in said casing -to channel theinfluent liquid through the wire wrappings, and channel means from Atheunderside of the wires to the outle't liquid ports.

Referring to Figs. 1, 24 and 3, a preferred embodiment of afilter-heater I0 of the present invention comprises a central hollowmandrel II, the preferred form of said mandrel being tubular, radialribs I2 carried by the mandrel II and wrappings of wire I3 supported onsaid ribs I2. End members Il and I5 are suitably fastened to the ribsand/or mandrel IAI and provide bases for anchoring the wire I3. The endmembers Il and I5 may, for example, be welded to the ribs I2,'or haveinternal threads I6 for engagement with vthreads on the constricted endsIl of the ribs I2 as shown in the lower parts of Fig. 1. The ends of thewire or wires I3 may be soldered, welded. bolted or fastened in anydesired manner to the end members I4 and I5 at 44. 4

Adjacent the end member Il is a removable end plug or other 4closuremeans I8 having an axial bore 21|, an enlarged portion 33 of said borebeing formed within an extended wall 22 of the element I8, whereby anannular passageway I9 is provided around an extended, ribless end 39 ofmandrel II, said annular passageway ISI being adapted to receive iiuidflowing from grooves 20 formed between the'ribs I3 on the mandrel II, asshown in Fig. 2. The wall Vl2 of the element I8 contains one or moreperforations or fluid openings 23.

'I'he -axial bore 2I of the end plug I'B is in register with the axialbore 24 of the extended, ribless end 39 of mandrel II, said end ofmandrel I I being positioned and removably secured in fluidtight contactwith wall 25 of end plug I8. The end plug I8 is removably connected,Ias` by a threaded connection 26, to an outer casing or housing 21surrounding and containing the wire wrapped mandrel II and the end plugelement I8. The other end of the casing 21 is closed by an end plug orother closure means 28 removably secured to or integrally united withsaid casing. The end plug 28 has an -axial bore 129 in register with theaxial Abore 24 of the wire wrapped mandrel I I,`said mandrel 'having ane'nd 30 positioned and removably secured in fluid-tight contact with awall 3I of end plug 28, while an end member I5 connected to the ribs I2by screw-threads I6 is removably positioned in fluid-tight contact witha wall 32 of end plug 28. Fluid-tight contact be-` tween th variousunits is secured in any desired manner, `as by thre-aded connections orby the use of ring seals 45 or packing in grooves cut in the variousunits as at 46.

Secured to the inside wall of the casing 21 sov ond annular closedchamber 35 around the fluid channeling element I8. Formedin the wall ofcasing -21 'in communication with the chamber 34 is-an inlet port 36 anda residue drain port 31, said ports being set preferably at least ninetydegrees to each other to prevent contaminating material from enteringthe inlet port 36. The drain -port 31 may be closed in any desiredmanner, as'by a removable cap or a valve, not shown. Located in thewall'of casing 21 in communication with the annular closed chamber 35 isan outlet port 4I) adapted for suitable attachment to a conduit. Theaxial bore 2| of the uid channeling element I8` and the axial bore 29 ofend plug 28 are adapted for suitable connection to a, fluid conduit, asby threaded connections shown at 4I and 42.

During the operation of the filter-heater of the present invention theliquid to be filtered enters inlet port 36` flowing into the annularclosed chamber 34, between the wrapplngs of wire I3 and thence along thelarge grooves between the ribs I2, into annular passageway I9, throughperforations 23, into annular closed chamber to be discharged throughoutlet port 40. At the same time a temperature controlling fluid flowswithin the central tubular mandrel through axial bores 29, 24 and 2|entering a threaded connection 4I and discharging at the oppositeconnection 42. For example, if a heated liquid or steam is passed withinthe tubular mandrel I I, thereby heating said` mandrel to a hightemperature, the heat supplied to the mandrel will flow by directconduction to the ends of the ribs I2 and thence to the Wire I3 incontact therewith: Due to the relatively high heat conductivity of themetallic elements I2 and I3 the Wire wrappings on the mandrel I I maythus be maintained at the desired temperature either to preventcontaminating maf terials from solidifying-and adhering to said wirewrappings or to prevent any of the liquid from crystallizing out andblocking the openings between the wires I3. In operation, thefilterheater is preferably positioned with the axial bore 24 in ahorizontal position so that any contaminating materials filtered fromthe liquid will settle along the inside casing wall where they may beeasily removed by opening the drain port 31.

" The ribs are formed integrally with or suitably fastened to themandrel II, as by welding, etc.,

and are preferably positioned to outline with their outer ends acylindrical surface around which the wire I3 is wrapped. It is realizedthat fluid carrying grooves will be formed under the wire wrappings I3when at least three ribs I2 are formed on the mandrel II. A greaternumber of ribs- I2 is used in the preferred embodiments of element I3,depending on the number of supporting ribs, may likewise be hexagonal,octagonal, etc., said shape approaching a true cylindrical surface asthe number of the ribs is increased, the term essentially cylindrical isused inthe present application. to cover equivalent variations intheshape of any of these elements capable of serving the same purposes astruly cylindrical elements. l'

Preferably, the outer radial edges of the ribs I2 are cut with helicalgrooves 43 to receive the helical -wrappings of wire I3. However, ifdesired; the outer radia1 edges of the ribs I2 may be smooth and thewire I3 Welded or soldered thereto. The wire may be suitably welded orsoldered after assembly in between each rib or over each rib so as toprevent unravelling in case of a broken wire. The purpose of this is toweld the wires together and not necessarily to weld them to thesupports.

The wire I3 may be formed with a rectangular cross-section havingspacing lugs formed thereon in a, conventional manner. However, roundwire; preferably of small diameter, yields several advantages when usedwith the structure of the present invention. The main advantages of sucha structure are, first, the shorter length of screen necessary for thesame screening capacity, and, second, a smaller amount of metal andother material needed to form the screen.

If a filter of lesser mechanical strength can be used where it isimportant to have a high screening capacity, the wrappings of wire maybe replaced by a wire screen or gauze of any desired mesh. Such a wiregauze may be formed around the ribbed mandrel and attached to saidmandrel and ribs in any desired manner, preferably by soldering.

Various modifications and changes may be made in the construction andarrangement of parts in the apparatus of the present invention withoutdeparting from the spirit of thepresent' invention as defined by thescope of the appended claims.

Certain elements of the present invention may be combined as shown inFig. 4 wherein the filter--I heater comprises two main parts. The firstpart consists `-of a casing 21 having an inlet port 36, v

an outlet port 40, a residue discharge port 31,

one end of the casing having an opening 4I leading to the axial bore 24,while the other end of said casing 21 isadapted to receive and be closedby the second-main port of the filter which conchannel the fluid outthedischarge port l1.

When necessary, th'e same type of filter may be used having inlet andoutlet fluid ports 80 and Bi' respectively located at the ends of thefilter beside the inlet andoutlet ports 62 and B3, to the ribbed mandrelas shown in Fig. 5. Or, the heating conduit may terminate on one side ofthe lter as shown at 13 in Fig. 6, where the other end of the conduit isat 12 and the inlet and outlet ports for the fluid to be filtered are'I0 and 1I respectively. Anoth'er .embodiment of the present inventionis shown in Fig. 7 wherein the flow filtered I of the filtered fluidthrough the apparatus is retween ribs 86 on mandrel 89, and out betweenthe wires 81 to be discharged at the outlet port 83. Any materials thusremoved from the liquid remain at all times in contact with the heatedsurfaces of the mandrel 89. ribs or wire 81 until they fall bygravityinto a sludge sump 88 which may be drained through discharge port Il.Heating fluid enters port 8|! and is discharged at Port l I.

I claim as my invention:

1. A filter device comprising a mandrel having an axial bore, aplurality of radial rib elements extending outwardly from said mandrel,a screen element supported on the outer ends of said ribsI to form ascreening surface surrounding said mandrel in spaced co-axialrelationship therewith. a closed housing surrounding said screen elementand spaced therefrom, a flange element amxed to the housing andextending inwardly into-`contact with said mandrelv to divide the spacebetween said housing and said screen element into two chambers, a portthrough the housing to supi ply the liquid to be iiltered to one of saidchambers, a port through the wail oi' the housing to withdraw saidliquid from the other chamber. and port means through th'e walls of saidhousing in register with the axial bore through the mandrel,

whereby the heat supplied to said mandrel by a means of a temperaturecontrolling fluid admitted to said bore through said port means istransmitted by conduction through said ribs to said screen element.

2. A filter device comprising a closed essentially u cylindricalhousing, an essentially cylindrical screen element within said housingin spaced coaxial relationship therewith. an essentially cylindricalmandrel within said screen element said mandrel having an axial bore,longitudinal rib elements radially extending from said mandrel tosupport said screen element in spaced vco-axiai relationship with saidmandrel. a flange element withinsaid' housing dividing the annular spacei between said housing and said screen element into two longitudinallyadjacent chambers, a port through the housing to supply ithe liquid tobe` filtered to one of said chambers. a port through the housing towithdraw said liquid from the other chamber, and port means through thewalls of said housing in register with the axial bore through themandrel, whereby the heat supplied to said mandrel by means of atemperature controlling iiuid admitted to said bore through said portmeans is transmitted by conduction through said ribs to said screenelement.

3. `A filtering device comprising an elongated mandrel member having anaxial bore, a Diumaior portion of the mandrel member to `form ribbed andribless portions of said member, said ribs extending radially outwardsto a substantial distance thus forming a seriesof grooves around saidmandrelmember, a filter screen element circumscribing and supported bythe ribs, an elongated outer housing member surrounding said mandrelmember, transverse 'ange means between the housing member and the screendefining a first chamber around the ribbed end of said mandrel and asecond chamber around the ribless end of said mandrel, -iirst port meansthrough th'e outer housing member to the first chamber, second portmeans through said outer housing member to the second chamber', a firstclosure means at one end of said housing member closing s econd chamberand adapted to seat the ribless end of themandrel, said first closuremeans having a perforated extended wall forming a passageway around saidribless portion of the mandrel, said passageway communicating with thegrooves between the ribs and being in communication with' the secondclosed chamber through the perforations in said extended wall, a secondclosure means at the other end of said housing member closing said firstchamber and adapted to seat the ribbed end of the mandrel member,and'port means through first and second closure means in register withthe aixal bore through the mandrel, whereby th'e heat supplied to saidmandrel by means of a temperature controlling fluid admitted to saidbore .through said portmeans is transmitted by conduction through saidribs to said screen element.

4. A/filtering device comprising an elongated ma el member having anaxial bore, a pluof ribs extending longitudinally along a idle portionof the mandrel member to form ibbed center portion and ribless endportions of said mandrel member, said ribs extending radially outwardsto form a series of grooves around said mandrel member, a filter screenelement circumscribing and supported by the ribs, an elongated outerhousing member surrounding said mandrel member, first and secondtransverse flange means between said housing member and the screenelement defining a first and a second chamber around the ribless ends ofthe mandrel member and a third chamber around the ribbed center portionof said mandrel member, a first closure means at one end of said housingmember closing the first chamber and adapted to seat one end of saidmandrel member. port means to said first chambensaid first closure meanshavinr a perforated wall forming a passageway around one ribless endportion of the mandrel, said passageway communicating with the groovesbetween the ribs and. being in communication with the first closedchamber through the perforation in said extended wail, a-second closuremeans at the other end oi' said housing member closing the secondchamber and adapted to seat the other end of said mandrel member, saidsecond chamber communicating withv the grooves between the ribs.normally closed port means to said secondi chamber, port means through'said housing member to said third chamber, and port means through thefirst and second closure means in register with the axial bore throughthe mandrel, whereby the heat supplied to said mandrel by means of atemperature controlling fluid admitted to said bore through said portmeans is transmitted by conduction through said ribs to said screenelement.v

WILFREDB.CRAKE.

